User blog comment:Thornclaw Braveheart/Ask Thornclaw 2.0/@comment-2207385-20120122190903/@comment-2231917-20120123052251

I can answer this! If he'll let me.

The pokemon generates a tractor beam, of sorts, and draws in the poke. Then, it lets the pokemon's atoms be converted into energy. Then turned back. Therefore, the red flash.